625g/1lb 6oz strong white bread flour, plus extra for dusting
75g/2½oz caster sugar
12g fine sea salt
40g/1½oz fresh yeast
500g/1lb 2oz chilled unsalted butter, plus extra to serve
1 free-range egg and 1 egg yolk, lightly beaten
raspberry jam, to serve
Method
The day before you want to bake the croissants, place the flour, sugar, salt and yeast in the bowl of a food mixer fitted with a dough hook, or a large mixing bowl. Pour in 350-400ml/12-14fl oz cold water and mix until it comes together as a soft dough.
Turn out the dough onto a lightly floured work surface and knead for a good 8-10 minutes, or until the dough feels smooth, stretchy and elastic. Return to the bowl and set aside to rest.
Sandwich the chilled butter between two sheets of greaseproof paper and roll out to a 30x20cm/12x8in rectangle, about 1cm/½in thick. Chill in the fridge until needed.
Turn the dough out again onto a lightly floured work surface. Roll it into a rectangle 60x30cm/24x12in.
Peel the greaseproof paper from the butter and place the butter centrally on top of the pastry rectangle.
Fold one edge of the pastry over the butter to half-cover it, then do the same with the other edge of the pastry so that the butter is covered.
Fold the rectangle in half lengthways, then give it a quarter-turn and roll out again to a rectangle measuring 60x30cm/24x12in..
